A fingerprint authentication device that, in the case where an authentication result indicating that a fingerprint authentication process has failed has been obtained, requests a corresponding user to re-input a fingerprint image has conventionally been known (see, for example, Japanese Laid-open Patent Publication No. 2003-296717).
More specifically, the conventional fingerprint authentication device judges whether the fingerprint authentication process has successfully been performed, based on a comparison result obtained by comparing input fingerprint information generated from a fingerprint image that has been input through a fingerprint sensor with registered fingerprint information that has been registered in advance. In this situation, in the case where an authentication result indicating that the authentication process has failed has been obtained, the fingerprint authentication device requests the user to re-input a fingerprint image, except in the situation where the input fingerprint information and the registered fingerprint information do not overlap each other at all.
A problem with the conventional fingerprint authentication device, however, is that the fingerprint authentication device requires more time and effort from the user during the fingerprint authentication process by requesting the user to re-input a fingerprint image in vain. In other words, even in a situation where the re-input of a fingerprint image will fail to bring out an authentication result indicating that the authentication process has successfully been performed, the conventional fingerprint authentication device requests the user to re-input a fingerprint image and requires more time and effort from the user during the fingerprint authentication process.